Vehicles can be equipped with side air bags, which may be in the form of an air bag disposed within a vehicle seat assembly. One limitation of air bags that are located within a seat assembly, is that the air bag needs to break through the seating material before it can fully deploy to protect a vehicle occupant. During deployment, such an air bag may encounter foam, or other seat pad materials, and must then break through a seat trim cover in order to escape from the seat assembly. Another limitation is that the air bag should break through the cover material at a predetermined location to optimize effectiveness. Other limitations are that the incorporation of the air bag in the seat assembly should not cause discomfort or safety issues to occupants.
Prior vehicle seat assemblies equipped with side air bags and manufacturing methods are disclosed in U.S. Pat. Nos. 5,860,673, 5,997,032 and 6,045,151, for example.